ELECTRIC TRANSMISSION DEVICE FOR RELATIVELY ROTATING PART

The purpose of the present invention is to provide an electric transmission device provided on a relatively rotating part of a machine device, wherein magnetic properties can be made stable and damagecaused by contact of two magnetic elements can be avoided, and which can be assembled easily. An electric transmission device (E) is provided with a pair of magnetic elements (1A, 1B) capable of relative rotation on the same center axis (O) as each other. Each of the magnetic elements (1A, 1B) has a core (2A, 2B) and a coil (3A, 3B) having conductive wire. The coil (3A) and the coil (3B) are respectively positioned outside and inside in the radial direction and are magnetically bound. Bobbins (4A, 4B) have circular cylindrical parts (4aA, 4aB) around the outer periphery of which the conductive wire is wound, and disk shaped flange parts (4bA, 4bB) that extend in an outward radial direction from the end of the circular cylindrical parts (4aA, 4aB) in the axial direction. The flange part (4bA) and the flange part (